I can't speak specifically about that issue since I'm not sure what combination of things they use but if a bolt can't lock back when cycling by hand it's a sure sign that the buffer tube is too short or buffer is too long and you would probably damage the tube or threads on the lower if you shoot it like that.
I know on their ar15 platform guns they use a commercial tube that's wider than a milspec tube. However AR10 and AR15 tubes are NOT interchangeable. If a bolt travels back too far it will damage the lower.
I know on their ar15 platform guns they use a commercial tube that's wider than a milspec tube. However AR10 and AR15 tubes are NOT interchangeable. If a bolt travels back too far it will damage the lower.